1. Field of the Invention
The present invention relates to a data driving circuit, a light emitting display device using the same and a driving method of the light emitting display device, and more particularly, to a data driving circuit capable of displaying an image of uniform brightness, a light emitting display device using the same and a driving method of the light emitting display device.
2. Discussion of Related Art
Recently, various flat panel display devices have been developed to have weights and volumes that are less than cathode ray tubes. The flat panel display devices include liquid crystal display devices, field emission display devices, plasma display panels, light emitting display devices, etc.
As a flat panel display device, a light emitting display device presents images using a light emitting diode that generates the light by recombining electrons and holes. Such a light emitting display device has an advantage of having a high speed of response, as well as of being driven at a low power (i.e., having a low power consumption).
FIG. 1 is a diagram showing a conventional light emitting display device.
Referring to FIG. 1, the conventional light emitting display device includes a display region 30 including a plurality of pixels 40 connected with scanning lines S1 to Sn and data lines D1 to Dm; a scan driver 10 for driving the scanning lines S1 to Sn; a data driver 20 for driving the data lines D1 to Dm; and a timing controlling unit 50 for controlling the scan driver 10 and the data driver 20.
The timing controlling unit 50 generates a data driving controlling signal (DCS) and a scanning driving controlling signal (SCS) to correspond to synchronous signals supplied from the outside. The data driving controlling signal (DCS) generated in the timing controlling unit 50 is supplied to the data driver 20, and the scanning driving controlling signal (SCS) is supplied to the scan driver 10. In addition, the timing controlling unit 50 supplies data supplied from the outside to the data driver 20.
The scan driver 10 receives the scanning driving controlling signal (SCS) from the timing controlling unit 50. The scan driver 10 receiving the scanning driving controlling signal (SCS) generates a scanning signal, and the generated scanning signal is sequentially supplied to the scanning lines (S1 to Sn).
The data driver 20 receives the data driving controlling signal (DCS) from the timing controlling unit (or controller) 50. The data driver 20 receiving the data driving controlling signal (DCS) generates a data signal, and the generated data signal is supplied to the data lines (D1 to Dm) to be synchronized with the scanning signal.
The display region 30 receives a first power of a first power supply (ELVDD) and a second power of a second power supply (ELVSS) from the outside and then supplies them to each of the pixels 40. Each of the pixels 40 receiving the first power of the first power supply (ELVDD) and the second power of the second power supply (ELVSS) generates the light corresponding to the data signal by controlling a current to flow from the first power supply (ELVDD) to the second power supply (ELVSS) via the light emitting diode in response to the data signal.
That is, each of the pixels 40 generates the light of a predetermined brightness corresponding to the data signal in the conventional light emitting display device. However, the conventional light emitting display device has a problem in that it is unable to display an image of a desired brightness due to uneven threshold voltages and a deviation of electron mobility of the transistors included in the pixels 40 in the prior art. The threshold voltages of the transistors included in the pixels 40 are compensated to some extent by controlling a configuration of the pixel circuit included in each of the pixels 40, but the deviation of electron mobility is not compensated. Accordingly, there is need for a light emitting display device capable of displaying an even image (of uniform brightness) regardless of the deviation of electron mobility.